HO scale Helix - laying track

[buckykatt1]

Hey everyone,
it's been awhile since I was on here last. I've torn down the old layout and started making way on a much, much larger layout. I'm in the process of building a double decker layout using a helix...and I've run into a few issues. I want to use code 83 Shinohara flex track to make a double main with a 26" and 28" radius. Here's the dilema. First off, should I put cork roadbed down under the track, or just spike the track directly to the MDF? I've never worked with it before and I don't want to screw up a $400.00 Helix.
I've talked with a few local hobby stores and all the responses are the same. They suggest I use Bachmann EZ track, which would end up costing me about $250.00. No offense to Bachmann users, but I don't want to spend that much money on pre-ballasted track, especially since I can buy ALOT of flex track for that amount of money.
Seoncdly, is there a tool or a way that I can lay flex track while making sure I can get the exact curveture? I don't want to start running trains and find out the hard way that two auto rack trains went "bump" in the middle of the helix.
If anybody can help out with this situation I would greatly appreciate it. I don't want to take the "easy" way out, especially if it's gonna cost me an arm and a leg.
Thanks

[shortliner]

Make yourself a 2/3 circle or 1/2 circle template with 26" inside and 28" outside radius from Homasote and lay your curved tracks together, with the template between them, moving/sliding the template up as you go up the helix. I'd suggest painting or varnishing ALL sides of the MDF helix, as if you have ANY dampness, the MDF will absorb it from the air Laying cork is up to you, but be advised that any track-nails to hold your flex, will need drilling as you go - MDF is hard!

[lajry]

There should be 2"+ between the tracks on curves otherwise cars will be sideswiping each other, especially on longer cars..

[BR60103]

I know 3 companies that make curve gauges.
Tracksetta
Ribbonrail
Fastracks.

I own examples of the first two. Tracksetta is British and may not be easily available. Ribbonrail is American. Both of these fit inside the rails. Ribbonrail comes in more sizes -- I think they have 2" increments in radii. Tracksetta is more like 6" or even a foot or more. Tracksetta gauges are about twice a long as Ribbonrail which are uner 5".
I find the Tracksetta easier to use -- they slide between the rails easier. Ribbonrail are a bit tighter and I think the ends aren't rounded off.
Fastracks is Canadian and I haven't needed to buy any.

I'm not sure about the MDF. I feel that it's impossible to put pins in without pre-drilling. Roadbed might make the helix quieter but takes up vertical space.
On my layout I'm gluing down the track and roadbed, but I still have to use pins (not through the ties) to hold the curves in shape. I'm using WS Foam glue under the roadbed and Scenic Cement under the ties.

[JaBear]

All good advice. At the local club we just drill,and nail flex track directly to the MDF base,( we use 3mm MDF as roadbed if required, which I wouldn't in the helix).
BUT first seal the MDF!!! We use white primer, it helps brighten things up when working underneath the layout when wiring etc.
Cheers, the Bear.

[buckykatt1]

Hey guys, thanks for all of the insite. I've looked over everyone's posts and I think I'm going to do a little bit of everything.

Shortliner, thanks for the heads up about the MDF absorbing moisture. Our basement has burned out two dehumidifiers in the past because of how damn it can get if I don't stay on top of things, so I'm going to be painting this afternoon. I'm going to pass on the idea of making a template. I'm great at making cirlces that end up more like ovals , and that's just too advanced for me.

Andy, thanks for the spacing information on double main lines. I'd like to avoid sideswiping at all costs. I don't want to find an auto rack in the front end of any of my units.

BR60103, I've taken alot of your insite into consideration as well. Your right about Tracksetta (I couldn't find it anyplace in the U.S.). So I've already gotten 24", 26" and 28" curve gauges on order from Ribbonrail. I want to make sure I lay these tracks down without any problems (especially in the helix)!

JaBear, the helix came with 1/4" MDF. I guess Ashlin Designs went to this material after having used wood, not sure as to why...I'll see how difficult it is to lay flex track in the helix (and securing it for that matter) and I'll keep everyone updated.
Again, thanks everyone for the help and insite. I feel the need to go build.....